Colony Collapse Disorder, diseases, parasitic mites and other stressors
continue to take a devastating toll on U.S. honey bee populations, but
Pennsylvania beekeepers on average fared better than their counterparts
nationally during this past winter, according to apiculture experts in
Penn State's College of Agricultural Sciences.

A recent survey by the Apiary Inspectors of America found that
losses nationwide topped 36 percent of managed hives between September
2007 and March 2008, compared to a 31 percent loss during the same
period a year earlier.

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Pennsylvania fared better, with losses of about 26 percent, compared
to nearly 48 percent the previous year. "About 70 percent of the
state's losses this year were not related to Colony Collapse Disorder,"
said Dennis vanEngelsdorp, acting state apiarist for the Pennsylvania
Department of Agriculture and a Penn State senior extension associate
in entomology.

He said the state's lower overall bee-mortality rate may be due to
greater awareness of bee health issues and beekeepers' diligence in
controlling varroa mites, nosema and other threats. He pointd out that
weather conditions also may have been more favorable for winter
survival.

vanEngelsdorp noted that the state's comparatively lower losses
meant that beekeepers this spring were able to meet the pollination
demands of Pennsylvania's $61 million apple industry, which is the
fourth largest in the country. Apples are completely dependent on
insects for pollination, and 90 percent of that pollination is
accomplished by honey bees.

"However, the cost of pollination has risen dramatically," he said
"This year, apple growers paid about $65 per colony, compared with $35
to $45 in the past." A typical apple orchard requires one colony per
acre to achieve adequate pollination. Last year, apple growers
harvested about 21,500 acres.

Later this year, pumpkin growers may pay $95 to $105 per colony, compared to $55 to $65 last year, vanEngelsdorp said.

Meanwhile, Penn State researchers are making progress in pinning
down the cause or causes of Colony Collapse Disorder (CCD), a
mysterious ailment that threatens the beekeeping industry and the crops
and native plants that rely on honey bees for pollination.

In fall 2007, a team led by Diana Cox-Foster, professor of
entomology, reported a strong correlation between CCD and the presence
of Israeli acute paralysis virus, making the pathogen a prime suspect
in the disease. Since that time, researchers have introduced IAPV to
healthy honey bee colonies in a controlled greenhouse environment in an
effort to induce a collapse.

"Within one week of introducing the virus, we observed dramatic bee
mortality, with bees dying outside the colonies across the room in the
greenhouse," said Cox-Foster. "Bees were found on the floor with
paralytic-type movements, and guard bees were observed removing
paralytic bees from colonies and flying across the room. The majority
of these 'twitcher' bees were found to have IAPV."

Cox-Foster noted that within a month, infected colonies had declined
to small clusters of bees, many of which had lost their queens. "These
data indicate that IAPV is a highly pathogenic virus," she said. "But
they do not yet support a finding of IAPV as the sole cause of Colony
Collapse Disorder. We still suspect that additional stresses are needed
to trigger CCD."

Among the potential triggers being investigated are environmental
chemicals. Penn State scientists analyzing pollen, wax, adult bees and
brood (larvae) have found the presence of dozens of chemicals,
including pesticides used by agricultural producers to protect crops
and by beekeepers to control hive pests such as parasitic mites.

"This raises several complicated questions," said Maryann Frazier,
senior extension associate in entomology. "Some of these compounds
could react with each other to cause toxic effects or could combine
with viruses or poor nutrition to weaken immunity and cause colony
collapse. We also need to do more research to understand these
chemicals' sub-lethal effects on bees."

Though the role of chemicals in Colony Collapse Disorder is still
unknown, Frazier noted that beekeepers need more options for
controlling varroa mites so they can reduce their reliance on
chemicals. "With the sheer number of compounds we're finding in hives,
it's hard to believe that pesticides aren't contributing to the general
decline in bee health," she said.